I gave the enemy a clipboard

In a tower-defense the enemies are the passive ones. They walk a line; you do things to them. Even the hostile structures I’d added earlier just sat there and buffed the wave — annoying, but static. I wanted the opposite: an enemy that reaches over and messes with your side of the board while it walks.

So I hired an inspector.

The Regulator

The Regulator is a walking saboteur — an AI-compliance officer in a long coat, clipboard in one hand, a red INSPECTION stamp in the other. He doesn’t attack. He audits. Every few seconds as he crosses the funnel he serves a citation: a flat fine skimmed off your cash, and the nearest serve tower flagged offline for five seconds. Then he keeps strolling and does it again.

He’s deliberately tanky, and the reason is a bit of the game’s own logic turned against you. Under the hood every serve is a rock-paper-scissors match — a tower only really satisfies a customer whose demands it answers. The Regulator craves privacy above all, which most towers are bad at, so generic fire barely dents him. You can bring him down — satisfy his bar and he “converts,” paying a fat bounty, the in-fiction equivalent of lobbying him into approval — but it costs real, focused effort. Ignore him and you eat a fine-and-audit every few seconds for his entire crossing.

The detail I can’t stop grinning about: he walks straight through your compliance gates — the Cookie Consent / GDPR / AI Act walls you drop to jam the lane. Of course he does. He’s the one who wrote them.

He was mostly spare parts

Here’s the thing about a good “new” mechanic — the best ones are already in your codebase, pointed somewhere new. The bosses in this game already had two moves I wanted: an Alignment Audit that disables your strongest tower, and a money-slash. The Regulator’s whole toolkit is those two, minus the boss.

The wrinkle was cadence. A boss fires abilities on a scripted timer; a regular unit doesn’t have one. So the Regulator carries a little countdown of his own — every few seconds of walking, it trips, and I point it at the same disable-and-fine the bosses use. The one real refactor: the old code could only track one disabled tower at a time (a boss only audits once). Two Regulators, or a Regulator plus a boss, would step on each other. I swapped the single slot for a map of “tower → time it reboots,” so any number of sources can take towers offline independently and each recovers on its own clock. Walking through walls was a single flag: this unit ignores barriers.

The bug that was really a UI bug

Then I played it and my towers kept going quiet for no visible reason. My damage would sag, I’d squint, and a few seconds later it came back. The Regulator was working perfectly. I just couldn’t see it.

The old disable effect was a quarter-second flash — completely fine for a boss move that happens once a fight, and completely useless for something that re-fires every few seconds. A recurring mechanic has a higher bar for legibility than a one-shot: if it keeps happening, the player has to be able to read it every single time.

So I gave any offline tower a persistent, pulsing warning badge that stays up for the whole downtime — and that quietly fixed every other disable in the game. The boss audit, the rogue AI’s shutdowns, a titan’s scorched-earth trail — all of them had been flashing for a quarter-second and hoping you noticed. One recurring enemy forced the legibility the one-shot versions had let me skip.

Keeping him in his lane

A tower-thief is a real spike, so he’s fenced in. He joins each world’s roster late, he’s capped at one per wave — his fines and audits stack brutally otherwise — and he’s banned from boss levels entirely. Those fights are tuned by a headless bot that can’t model “an inspector unplugged my best tower mid-titan,” so letting him crash the party would quietly wreck balance I’d spent a long time on.

What it changed

Every other threat in this game is a health bar walking toward the exit. The Regulator is the first enemy that reaches back across the board and touches your economy and your towers directly. That flips the question from “did I build enough” to “that guy is bleeding me every few seconds — do I pull fire off the wave to shut him down now, or tank it and keep converting?” It’s a genuine decision, built almost entirely from parts I already had — and the hardest part wasn’t making him audit you. It was making sure you could tell when he did.